ARCHITECT’S HANDBOOK of Construction Detailing
SECOND EDITION ARCHITECT’S HANDBOOK of Construction Detailing David Kent Ballast, FAIA, CSI John Wiley & Sons, Inc.
This book is printed on acid-free paper. ∞ Copyright C 2009 by John Wiley & Sons, Inc. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600, or on the web at www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at www.wiley.com/go/permissions. Limit of Liability/Disclaimer of Warranty: While the publisher and the author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor the author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. For general information about our other products and services, please contact our Customer Care Department within the United States at (800) 762-2974, outside the United States at (317) 572-3993 or fax (317) 572-4002. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. For more information about Wiley products, visit our web site at www.wiley.com. Library of Congress Cataloging-in-Publication Data: Ballast, David Kent. Architect’s handbook of construction detailing / David Ballast. – 2nd ed. p. cm. Includes bibliographical references and index. ISBN 978-0-470-38191-5 (cloth : alk. paper) 1. Building–Details–Drawings. I. Title. TH2031.B35 2009 692’.2–dc22 2008047065 Printed in the United States of America. 10 9 8 7 6 5 4 3 2 1
CONTENTS List of Tables xi Preface xiii Acknowledgments xv Introduction xvii How SI Units Are Used in this Book xix Abbreviations xxi 1 CONCRETE DETAILS 1 1-1 Concrete Slab-on-Grade Tolerances 03 05 03 1 1-2 Cast-in-Place Concrete Sectional Tolerances 03 05 04 4 1-3 Cast-in-Place Concrete Plan Tolerances 03 05 05 5 1-4 Waterstops 03 15 13 7 1-5 Slab-on-Grade Control Joint 03 30 07 9 1-6 Slab-on-Grade Isolation Joint 03 30 08 12 1-7 Slab-on-Grade Construction Joint 03 30 09 14 1-8 Cast-in-Place Concrete Wall with Insulation 03 30 53 16 1-9 Architectural Concrete 03 30 00 19 1-10 Precast Concrete Spandrel with Insulation 03 40 01 22 1-11 Precast Concrete Beam and Double Tee Tolerances 04 41 00 25 1-12 Autoclaved Aerated Concrete Panels 04 22 23.1 27 1-13 Architectural Precast Concrete Panel Tolerances 03 45 13 30 1-14 Architectural Precast Panel Size and Configuration 03 45 14 32 1-15 Architectural Precast Concrete Forming 03 45 15 34 1-16 Architectural Precast Corners 03 45 16 36 1-17 Architectural Precast Joints 03 45 17 39 1-18 Architectural Precast Weathering Details 03 45 18 40 1-19 Architectural Precast Panel Connections 03 45 19 42 1-20 Architectural Precast Spandrel Panels 03 45 20 44 1-21 Architectural Precast Parapet 03 45 21 45 1-22 Cast-in-Place/Precast Connection 03 45 90 47 1-23 Precast Floor/Beam Erection Tolerances 03 45 91 49 1-24 Glass Fiber Reinforced Concrete Panels 03 49 00 51 2 MASONRY DETAILS 55 2-1 Vertical Concrete Masonry Expansion Joint 04 05 23.1 55 2-2 Vertical Brick Expansion Joint 04 05 23.2 58 v
vi Contents 2-3 Vertical Masonry Expansion Joint in Composite Wall 04 05 23.3 62 2-4 Brick/Masonry Cavity Wall at Grade 04 21 10.1 65 2-5 Brick/Masonry Cavity Wall at Spandrel 04 21 10.2 69 2-6 Brick/Masonry Cavity Wall at Roof/Parapet 04 21 10.3 71 2-7 Masonry Grouted Wall 04 21 10.4 74 2-8 Brick Veneer, Wood Studs 04 21 13.1 78 2-9 Brick Veneer, Steel Stud Backing Wall 04 21 13.2 82 2-10 Brick Veneer, Steel Stud Backup Wall at Opening 04 21 13.3 87 2-11 Brick on Shelf Angle 04 21 13.4 91 2-12 Shelf Angle on Steel Framing 04 21 13.5 96 2-13 Interior Masonry Bearing Partition 04 22 01 99 2-14 Wood Joists on Interior Masonry Bearing Partition 04 22 02 101 2-15 Autoclaved Aerated Concrete Masonry 04 22 26 102 2-16 Reinforced Concrete Masonry Wall at Grade 04 22 23.1 104 2-17 Reinforced Concrete Masonry Wall at Floor 04 22 23.2 107 2-18 Reinforced Concrete Masonry Wall at Parapet 04 22 23.3 109 2-19 Glass Block Wall at Sill and Head 04 23 13.1 110 2-20 Glass Block Wall at Jamb and Vertical Joint 04 23 13.2 113 2-21 Glass Block Wall—Alternate Details 04 23 13.4 115 2-22 Anchored Stone Veneer with Concrete Masonry Unit Backup at Grade 04 42 13.1 116 2-23 Anchored Stone Veneer with Concrete Masonry Unit Backup at Spandrel 04 42 13.2 120 2-24 Anchored Stone Veneer with Concrete Masonry Unit Backup at Parapet 04 42 13.3 122 2-25 Exterior Stone Veneer at Base 04 42 13.4 125 2-26 Exterior Stone Veneer at Spandrel 04 42 13.5 129 2-27 Exterior Stone Veneer at Parapet 04 42 13.6 130 2-28 Cut Stone on Concrete Backup Wall 04 42 13.7 132 2-29 Interior Stone Veneer 134 2-30 Interior Stone Veneer at Vertical Joint 04 42 16.2 135 2-31 Exterior Stone on Steel Truss Frame 04 42 23 136 2-32 Exterior Stone on Framing System 04 42 26 139 3 METAL DETAILS 143 3-1 Structural Steel Column Erection Tolerances 05 05 03 143 3-2 Steel Column/Beam Connection Tolerances 05 05 03.1 145 3-3 Structural Steel Column Plan Tolerances 05 05 04 146 3-4 Structural Steel Column Location Tolerances 05 05 04.1 148 3-5 Structural Steel Support for Masonry 05 12 23.1 150 3-6 Structural Steel Support for Precast Concrete 05 12 23.3 152 3-7 Steel/Precast with Insulation 05 12 23.3 153 3-8 Structural Steel Support for Curtain Walls 05 12 23.5 155
Contents vii 3-9 Open Web Steel Joists 05 21 19 157 3-10 Stair Layout 05 51 00.1 158 3-11 Stair Layout at Base 05 51 00.2 160 3-12 Stair Layout at Landing 05 51 00.3 161 3-13 Stair Layout at Top Landing 05 51 00.4 162 3-14 Metal Stairs 05 51 13 164 3-15 Ornamental Metal/Glass Guard 05 52 13 165 3-16 Expansion Joint at Floor and Wall 05 54 00.1 166 4 WOOD DETAILS 169 4-1 Platform Framing at Foundation 06 11 00.1 169 4-2 Platform Framing at Stepped Foundation 06 11 00.2 172 4-3 Platform Framing at Roof 06 11 00.3 173 4-4 Multistory Framing at Foundation 06 11 00.4 175 4-5 Multistory Framing at Floor Line 06 11 00.5 177 4-6 Multistory Framing at Roof 06 11 00.6 178 4-7 Structural Insulated Panel at Foundation 06 12 00.1 179 4-8 Structural Insulated Panel at Roof 06 12 00.2 182 4-9 Glulam Beam at Foundation Wall 06 18 13.1 183 4-10 Glulam Beam at Column 06 18 13.2 185 4-11 Glulam Purlins at Beam 06 18 13.3 186 4-12 Glulam Roof Beam 06 18 13.4 188 4-13 Glulam Column at Base 06 18 16 190 4-14 Base Cabinet 06 41 00.1 191 4-15 Upper Cabinet 06 41 00.2 193 4-16 Countertops 06 41 00.3 195 4-17 Shelving 06 41 00.4 197 4-18 Flush Wood Paneling 06 42 16 199 5 THERMAL AND MOISTURE PROTECTION DETAILS 203 5-1 Foundation Waterproofing 07 13 00 203 5-2 Cold, Liquid-Applied Membrane Deck Waterproofing 07 14 00.1 206 5-3 Vegetated Protected Membrane Roofing 07 55 63 209 5-4 Slab-on-Grade Foundation Insulation 07 21 13 212 5-5 Weather Barrier Concepts 213 5-6 Exterior Insulation and Finish System at Base 224 5-7 Exterior Insulation and Finish System at Parapet 229 5-8 Exterior Insulation and Finish System Openings 231 5-9 Asphalt/Glass Fiber Shingles at Eaves 07 31 13 232 5-10 Wood Shingles at Eaves 07 31 29 235 5-11 Roofing Tiles at Eaves 07 32 00 237
viii Contents 5-12 Preformed Metal Wall Panel at Base 07 42 13.1 238 5-13 Preformed Metal Wall Panel at Parapet 07 42 13.2 240 5-14 Roofing Systems on Steel Deck 07 22 00.1 241 5-15 Roofing Systems on Concrete Deck 245 5-16 Built-up Roof at Supported Deck 07 51 00.1 247 5-17 Built-up Roof at Nonsupported Deck 07 51 00.2 251 5-18 Built-up Roofing at Expansion Joint 07 51 00.3 252 5-19 Built-up Roof at Equipment Support 07 51 00.4 254 5-20 Built-up Roof at Stack Flashing 07 51 00.5 255 5-21 Modified Bitumen Roof at Supported Deck 07 52 00.1 256 5-22 Modified Bitumen Roof at Nonsupported Deck 07 52 00.2 260 5-23 Modified Bitumen Roof at Expansion Joint 07 52 00.3 261 5-24 Modified Bitumen Roof at Equipment Support 07 52 00.4 263 5-25 Modified Bitumen Roof at Plumbing Vent 07 52 00.5 264 5-26 EPDM Roof at Supported Deck 07 53 23.1 265 5-27 EPDM Roof at Nonsupported Deck 07 53 23.2 269 5-28 EPDM Roof at Expansion Joint 07 53 23.3 270 5-29 EPDM Roof at Equipment Support 07 53 23.4 272 5-30 EPDM Roof at Pipe Flashing 07 53 23.5 273 5-31 TPO Roof at Supported Deck 07 54 23.1 274 5-32 TPO Roof at Curb Threshold 07 54 23.2 277 5-33 TPO Roof at Expansion Joint 07 54 23.3 279 5-34 TPO Roof at Equipment Support 07 54 23.4 280 5-35 TPO Roof at Pipe Flashing 07 54 23.5 282 5-36 Protected Membrane Roofing 07 55 00 283 5-37 Gravel Stop 07 71 19 284 5-38 Vertical and Horizontal Joint Fillers and Sealants 07 92 00 286 5-39 Roof Drain 22 14 26.13 294 6 DOOR AND WINDOW DETAILS 297 6-1 Steel Door and Frame Jamb, Masonry Wall 08 11 13.1 297 6-2 Steel Door and Head Frame, Masonry Wall 08 11 13.2 300 6-3 Steel Door and Frame, Gypsum Wallboard Wall 08 11 13.3 302 6-4 Aluminum Door Frame Assembly 08 11 16 305 6-5 Wood Door and Frame Assembly 08 14 00 306 6-6 Aluminum Storefront at Sill and Head 08 41 13.1 309 6-7 Aluminum Storefront at Mullion and Jamb 08 41 13.2 311 6-8 All-Glass Entrance Door 08 42 26.1 312 6-9 All-Glass Glazing System 08 42 26.2 314 6-10 All-Glass Glazing System at Mullion and Jamb 08 42 26.3 315 6-11 Aluminum Curtain Wall at Spandrel 08 44 13.1 316 6-12 Aluminum Curtain Wall at Roof 08 44 13.1 320 6-13 Aluminum Curtain Wall at Mullion 08 44 13.2 322
Contents ix 6-14 Four-sided Structural Silicone Glazing at Spandrel 08 44 26.1 324 6-15 Four-sided Structural Silicone Glazing at Mullion 08 44 26.2 328 6-16 Aluminum Window, Masonry Wall 08 51 13.3 329 6-17 Steel Window, Masonry Wall 08 51 23 331 6-18 Wood Window, Masonry Wall 08 52 00.3 333 6-19 Wood Window, Wood Frame Wall 08 52 00.4 335 6-20 Interior, Framed Glazed Opening at Jamb 08 81 00.1 336 6-21 Interior, Framed Glazed Opening at Sill and Head 08 81 00.2 338 6-22 Interior Frameless Glazed Opening at Jamb 08 81 00.3 339 6-23 Interior Frameless Glazed Opening at Sill and Head 08 81 00.4 341 6-24 Interior Fire-Resistant Rated Glazing 08 88 60 342 7 FINISH DETAILS 347 7-1 Gypsum Wallboard Shaft Lining 09 21 16 347 7-2 Gypsum Wallboard, Nonrated Partition 09 29 03.1 350 7-3 Gypsum Wallboard, Slip Joint at Structural Slab 09 29 03.2 353 7-4 Gypsum Wallboard, Proprietary Slip Joint 09 29 03.3 356 7-5 One-Hour Gypsum Wallboard Partition, Wood Framing 09 29 03.4 357 7-6 Sound-Rated One-Hour Gypsum Wallboard Partition 09 29 03.5 359 7-7 One-Hour Gypsum Wallboard Partition, Metal Framing 09 29 03.6 361 7-8 Two-Hour Gypsum Wallboard Partition, Wood Framing 09 29 05.1 363 7-9 Two-Hour Gypsum Wallboard Partition, Metal Framing 09 29 05.2 365 7-10 Three-Hour Gypsum Wallboard Partition 09 29 07.1 367 7-11 Three-Hour Fire-Rated Column Cover 09 29 07.2 369 7-12 Perimeter Relief Joint 09 29 09 370 7-13 One-Hour Gypsum Wallboard Ceiling, Wood Framing 09 29 11.1 372 7-14 Two-Hour Suspended Gypsum Wallboard Ceiling 09 29 11.2 373 7-15 Ceramic Tile Floor, Thin-Set on Wood Framing 09 31 13.1 375 7-16 Ceramic Tile Wall, Thin-Set 09 31 13.2 378 7-17 Movement Joint with Thin-Set Tile 09 31 13.3 380 7-18 Ceramic Tile Floor, Thick-Set on Membrane Over Concrete 09 32 13.1 382 7-19 Ceramic Tile Floor, Full Mortar Bed 09 32 13.2 385 7-20 Ceramic Tile Ceiling 09 32 13.3 387 7-21 Ceramic Tile Wall, Full Mortar Bed 09 32 13.4 388 7-22 Ceramic Tile Expansion Joint 09 32 13.5 390 7-23 One-Hour Acoustical Ceiling Assembly 09 50 13.1 392 7-24 Two-Hour Acoustical Ceiling Assembly 09 50 13.2 394
x Contents 7-25 Stone Flooring, Thin-Set 09 63 40.1 396 7-26 Stone Flooring, Full Mortar Bed 09 63 40.2 397 7-27 Wood Parquet Flooring 09 64 23 399 7-28 Wood Strip Flooring on Wood Framing 09 64 29.1 401 7-29 Wood Strip Flooring on Concrete Framing 09 64 29.2 402 7-30 Laminate Flooring 09 62 19 404 7-31 Resilient Wood Flooring System 09 64 53 405 7-32 Portland Cement Terrazzo, Sand Cushion 09 66 13.13 407 7-33 Portland Cement Terrazzo, Monolithic 09 66 13.16 409 7-34 Portland Cement Terrazzo, Bonded 09 66 13.19 411 Appendix A: Standards Titles 415 Appendix B: Sources for More Information 423 CSI Six-Digit Number Index 431 Index 437
LIST OF TABLES Table 1-1 Concrete Aggregate Visibility 34 Table 1-2 Recommended Dimensions of 90 Degree Quirk Miters, in. (mm) 37 Table 1-3 Recommended Dimensions of 45 Degree Quirk Miters, in. (mm) 37 Table 2-1 Maximum Horizontal Spacing of Vertical Control Joints in Exterior Concrete Masonry Walls, in ft (m) 56 Table 2-2 Recommended Brick Joint Widths Based on Joint Spacing 61 Table 2-3 Maximum Glass Block Panel Sizes Based on International Building Code Limitations 111 Table 2-4 Minimum Radii of Curved Glass Block Walls 112 Table 2-5 Average Coefficients of Thermal Expansion of Building Materials 118 Table 2-6 Weights of Building Stone 127 Table 3-1 Open Web Steel Joists Series 157 Table 4-1 Materials and Thicknesses for Cabinet Components 193 Table 4-2 Maximum Allowable Total Load in Pounds (kg) for Shelf Deflection of 1/8 in. (3 mm) for Shelves of Different Materials, Widths, and Spans 198 Table 5-1 Insulation Requirements for Slabs-on-Grade 213 Table 5-2 Climate Zone Descriptions 215 Table 5-3 Perm Rating Terminology 216 Table 5-4 Minimum Thicknesses of Gravel Stops, in. (mm) 286 Table 5-5 Coefficients of Solar Absorption for Common Building Materials 289 Table 5-6 Heat Capacity Constants 289 Table 5-7 Coefficients of Linear Moisture Growth for Common Building Materials 290 Table 5-8 Recommended Depth of Sealants 291 Table 5-9 Comparative Properties of Sealants 293 Table 7-1 Maximum Stud Heights 354 Table 7-2 Recommended Ceramic Tile Expansion Joint Width and Spacing 381 xi
PREFACE While construction details can add to the style and aesthetic appeal of a building, they are useless unless they can successfully provide the basic functional requirements of satisfying the building’s purpose, protecting against the elements, providing durable interior finishes, and making construction efficient and economical. Most building problems and outright failures occur because of poorly designed or constructed details. Although detailing is vitally important for preventing problems, it is becoming a lost art at the same time that it is becoming more complex due to the proliferation of new materials and construction techniques, more stringent energy and sustainability requirements, and safety and security concerns. Architecture schools rarely provide students with the fundamental grounding in detailing and specifying or spend as much time on them as on design and other subjects. In architectural practice, final detailing is often left until the end of the design and documents phases, when time and money are limited, for their thorough development. The Architect’s Handbook of Construction Detailing provides architects, interior designers, contractors, students, and others involved with the construction industry with a convenient source of detailing and specification information on hundreds of commonly used details and materials. Although no one book can provide all the details that are used in construction, the Architect’s Handbook of Construction Detailing provides basic detail configurations that can be used as the basis for project-specific detail development. Because detailing is closely tied to specifying, this book also provides fundamental material data and information. The written information is coordinated with the illustrated details in a keynote format. The current edition of this book updates and expands features in the first edition. Details have been revised to reflect new technologies and more stringent requirements for energy conservation. New sections have been added on concrete with insulation, autoclaved aerated concrete, glass fiber reinforced concrete panels, precast concrete with insulation, multistory wood framing, structural insulated panels, vegetated protected membrane roofing, weather barrier concepts, thermoplastic polyolefin roofing, fire-resistant glazing, proprietary gypsum wallboard slip joints, and laminate flooring. The keynoting system has been updated from the previous Construction Specifications Institute’s five-digit MasterFormatTM numbering system to the current six-digit system. All illustrations have been redrawn and industry standard references, including ASTM and ANSI standards, have been updated, as have the sources for information in the appendices. As with the first edition, each detail section follows a similar format to make it easy to find information and relate it to the drawing. The details in the book may be used to help solve specific problems, as the basis for developing a master detail system, or as a reference for checking existing drawings and specifications. The book can also be used to develop and coordinate specifications with details. xiii
ACKNOWLEDGMENTS I would like to thank the many people who contributed to the making of this book. For the publisher John Wiley & Sons, Amanda Miller, vice president and publisher, and John Czarnecki, Assoc. AIA, senior editor, were instrumental in suggesting this new edition. Thanks also to the other fine people at John Wiley & Sons: Donna Conte, senior production editor; Sadie Abuhoff, editorial assistant; Helen Greenberg for copyediting; Figaro for design and page layout. xv
INTRODUCTION What This Book Will Do for You The Architect’s Handbook of Construction Detailing presents ready-to-use information about critical building details to help you produce construction drawings, design and develop custom details, prepare specifications, and check existing drawings in your files. The details presented can be used directly for common construction situations. If modifications are necessary for unique project conditions, the data presented with each drawing tell you what can and cannot be changed to maintain the integrity of the detail. The construction assemblies in this book have been selected to help you avoid problems in those areas where they are most likely to occur. Information presented in seven sections shows you how to detail such conditions as exterior cladding, roofing, doors, masonry, and many, many others so that you can prevent common mistakes that architects seem to repeat far too often. In addition to clearly drawn graphic details, accurate, to-the-point information is given to help you coordinate a detail with other parts of your design, specify materials, and develop your own layout if necessary. A broad range of architectural details is covered, from concrete construction to finishes. Each drawing has an identifying number according to the Construction Specifications Institute’s MasterFormat system, and all the pertinent materials used in the details are identified by the same numbering system. This makes it easy for you to produce drawings with time-saving keynoting, to coordinate the drawings and information with your specification system, and to supplement the details with your own data filing procedures. Most details have been drawn at three-inch scale. When another scale is used, it is shown at the bottom of the drawing. Among the many other details, this Handbook Shows the recommended way to detail concrete joints. (See Sections 1-5, 1-6, and 1-7) Specifies the most common concrete construction tolerances. (See Sections 1-1, 1-2, 1-3, 1-11, and 1-13) Presents common methods of assembling precast wall panels. (See Sections 1-16, 1-17, and 1-19) Describes how to assemble brick veneer walls to avoid cracks and leaks. (See Sections 2-9 and 2-11) Compiles the many ways stone veneer should be attached to concrete and steel frames. (See Sections 2-22, 2-23, 2-25, 2-26, 2-27, 2-31 and 2-32) Provides the secrets to designing elegant stairways. (See Sections 3-10 through 3-13) Simplifies the methods of forming expansion joints. (See Sections 2-2 and 3-16) Shows how to fabricate glued-laminated beam and column connections. (See Section 4-10) Tells how to create sheet membrane waterproofing details. (See Sections 5-1 and 5-2) Organizes information on asphalt and fiberglass shingles. (See Section 5-9) Lays out the many variations of single-ply roofing. (See Sections 5-16 through 5-36) Explains the dos and don’ts of joint fillers and sealants. (See Section 5-38) Illustrates steel door frame assemblies and what is involved in their proper construction. (See Sections 6-1. 6-2, and 6-3) xvii
xviii Introduction Describes how to detail a safety glass door. (See Section 6-8) Identifies the essential elements of steel, aluminum, and wood window detailing. (See Sections 6-16 through 6-19) Shows how fire-rated gypsum wallboard assemblies should be drawn. (See Sections 7-5 through 7-11) Illustrates the many ways to detail ceramic tile floors and walls. (See Sections 7-15 through 7-22) Gives guidance on detailing stone flooring. (See Sections 7-25 and 7-26) The information presented about each detail in this book follows a similar format to make it easy to find precisely the data required for your research. The first part of each detail information package shows the detail itself, with materials identified by MasterFormat number and other critical components dimensioned or labeled with design guidelines. Each of the components identified on the drawing by keynote number refers you to requirements for those materials given in the text. This gives you an invaluable guide for coordinating your drawings and specifications. The second part of the package consists of a brief description of the detail along with the limitations on using it. Then specific guidelines are presented to help you understand the critical points of construction and what must be considered in modifying the detail or developing your own. Next, points of coordination are listed to aid you in fitting the detail into the context of your design. Likely failure points are also outlined to alert you to common problems encountered in the design and construction of the detail. Finally, material and installation requirements for components of the detail are listed according to the keynote numbering system used in the detail. All of the information is presented in concise, easy-to-follow lists and notations so that you do not have to waste time wading through lengthy text. Appendices provide the full title of ASTM and other industry standards referred to in the book as well as sources for additional information if you want to do more research. The configuration of the details and accompanying data have been compiled from the most authoritative sources available. However, the material presented in this book should only be used as a supplement to normal, competent professional knowledge and judgment. This is because there are an unlimited number of variations of any basic detail to fit the requirements of a specific building project. In addition, factors outside the limits of a particular detail, such as structural loading, climate, and occupancy conditions, may impinge on the detail’s performance or exact method of construction. You may want to use the details in this book to help solve specific problems, as the basis for your office’s own master detail system, or simply as a reference for checking existing drawings. If you have master details on a computer-aided drafting system or an automated specification writing system, you may want to review those data to see if modifications or corrections are warranted. Regardless of how you use this book, you will find it a time-saving reference that can minimize errors and improve the technical documentation of your projects.
HOW SI UNITS ARE USED IN THIS BOOK This edition of the Architect’s Handbook of Construction Detailing includes equivalent measurements, using the Systeme Internationale (SI), in the text and illustrations. However, the use ` of SI units for construction and book publishing in the United States is problematic. This is because the building construction industry in the United States (with the exception of federal construction) has generally not adopted the metric system, as it is commonly called. Equivalent measurements of customary U.S. units (also called English or inch-pound units) are usually given as soft conversions using standard conversion factors. This always results in a number with excessive significant digits. When construction is done using SI units, the building is designed and drawn according to hard conversions, where planning dimensions and building products are based on a metric module from the beginning. For example, studs are spaced 400 mm on center to accommodate panel products that are manufactured in standard 1200 mm widths. During the transition to SI units in the United States, code-writing bodies, federal laws (such as the Americans with Disabilities Act [ADA]), product manufacturers, trade associations, and other construction-related industries typically still use the customary U.S. system and make soft conversions to develop SI equivalents. Some manufacturers produce the same product using both measuring systems. Although there are industry standards for developing SI equivalents, there is no consistency for rounding off when conversions are made. For example, the International Building Code (IBC) shows a 152 mm equivalent when a 6 in. dimension is required. The ADA Accessibility Guidelines shows a 150 mm equivalent for the same dimension. For the purposes of this book, the following conventions have been adopted. Throughout this book, the customary U.S. measurements are given first and the SI equivalents follow in parentheses. In the text, the unit suffixes for both systems, such as ft or mm, are shown. In the illustrations, the number values and U.S. unit suffixes are given first (in., ft, etc.) and the SI value after them in parentheses but without the unit if the number is in millimeters but with the unit if it is in meters or some other unit except millimeters. This follows standard construction practice for SI units on architectural drawings; a number is understood to be in millimeters unless some other unit is given. The exception to this convention occurs when a number is based on an international standard or product. In this case, the primary measurement is given first in SI units with the U.S. equivalent in parentheses. The unit suffix is shown for both in the text as well as in the illustrations to avoid confusion. When there is a ratio or some combination of units where it might be confusing, unit suffixes are used for all numbers—for example, 6 mm/3 m. When a standards-writing organization or a trade association gives dual units for a particular measurement, those numbers are used exactly as they come from the source. For example, one group might use 6.4 mm as the equivalent for 1/4 in., while another organization might use 6 mm. When an SI conversion is used by a code agency, such as the IBC or published in another regulation, such as the ADA Accessibility Guidelines (ADAAG), the SI equivalents used by the issuing agency are printed in this book. For example, the IBC uses a 152 mm equivalent xix
xx How SI Units are Used in This Book when a 6 in. dimension is required, while the ADAAG gives a 150 mm equivalent for the same dimension. If a specific conversion is not otherwise given by a trade association or standards-writing organization, when converted values are rounded, the SI equivalent is rounded to the nearest millimeter for numbers under a few inches unless the dimension is very small (as for small tolerances like 1/16 in.), in which case a more precise decimal equivalent is given. For dimensions over a few inches, the SI equivalent is rounded to the nearest 5 mm and to the nearest 10 mm for numbers over a few feet. When the dimension exceeds several feet, the number is rounded to the nearest 100 mm.
Abbreviations AAC autoclaved aerated concrete ACI American Concrete Institute AISC American Institute of Steel Construction AWI Architectural Woodwork Institute CFC chlorofluorocarbon ECH epichlorohydrin EN European Norms EPA Environmental Protection Agency EIFS exterior insulation and finish system EPDM ethylene propylene diene monomer EPS expanded polystyrene board FMG Factory Mutual Global (class ratings) FMRG Factory Mutual Research Corporation GFRC glass fiber reinforced concrete HCFC hydrochloro-fluorocarbon HFC hydrofluorocarbon HVAC heating, ventilation, air conditioning LEED Leadership in Energy and Environmental Design NFPA National Fire Protection Association NRC noise reduction coefficient NTMA National Terrazzo and Mosaic Association OSB oriented strand board PB polymer based PET polyethylene terephthalate PM polymer modified PVC polyvinyl chloride SBR styrene butadiene rubber SIP structural insulated panel STC Sound Transmission Class TPO thermoplastic polyolefin UL Underwriters Laboratories VOC volatile organic compound w.g. water gage XPS extended polystyrene board xxi
ARCHITECT’S HANDBOOK of Construction Detailing
CHAPTER 1 CONCRETE DETAILS 1-1 CONCRETE SLAB-ON-GRADE TOLERANCES Description Because no building can be perfectly level, plumb, and straight, there are certain acceptable tolerances for various types of construction, which have become industry standards. These tolerances give architects, engineers, and contractors allowable variations from given dimensions and elevations. Knowing these tolerances is important in detailing because allowances must be made for variations from idealized dimensions when several materials are connected, when clearances are required, or when appearance is critical. This section and Sections 1-2, 1-3, 1-11, 1-13, 1-22, and 1-23 give some of the industry standard tolerances regarding concrete construction. Slabs-on-grade (as well as elevated slabs) are subject to two tolerances. One is the overall tolerance above and below the specified elevation, and the other is the flatness and levelness of the floor finish. Flatness is the degree to which the surface approximates a plane. Levelness is the degree to which the surface parallels the horizontal plane. Limitations of Use These tolerances are for slabs-on-grade as specified by the American Concrete Institute (ACI). See Section 1-2 for tolerances of other slab surfaces. The tolerances given can also be used to specify sloped surfaces. Verify the size of temperature reinforcement, the concrete strength, and the size and spacing of rebars (if any) with a structural engineer. Detailing Considerations Do not specify a tolerance higher than that actually required for the project because higher finish tolerances generally cost more to achieve. For example, a moderately flat floor (±3/8 in. in 10 ft [10 mm in 3 m]) is generally sufficient for carpet or an exterior walk. Verify the slab thickness required for the project. A 4 in. (100 mm) slab is the minimum thickness allowable and is used for residential and lightly loaded commercial floors subject to foot traffic. A 5 in. (127 mm) thickness is required for light industrial and 1 Architect’s Handbook of Construction Detailing, Second Edition by David Kent Ballast Copyright © 2009 John Wiley & Sons, Inc.
2 Architect’s Handbook of Construction Detailing commercial floors where there is foot traffic and pneumatic wheeled traffic. Floors with heavy loads require thicker slabs and special reinforcing. Coordination Required In order to maintain the specified level of the slab, proper compaction and subgrade preparation must be specified and maintained during construction. Soil and fill under slabs should be compacted to 95 percent of standard Proctor density. Locate joints according to the information given in Sections 1-5, 1-6, and 1-7. Vapor barriers should be used under slabs to prevent moisture migration into the slab, to prevent shrinkage cracks, and to provide a barrier to radon penetration. However, in order to prevent plastic and drying shrinkage caused by differential water loss between the top and bottom of the slab, the slab must be properly cured following ACI recommendations. Reinforcing and concrete strength should be selected based on the service requirements of the slab. Generally, lightly loaded slabs require a minimum compressive concrete strength of 3500 psi (24,000 kPa), while light industrial and commercial slabs require a compressive strength of 4000 psi (27,500 kPa). Allowable Tolerances Level alignment tolerance is shown in Fig. 1-1(a). This means that over the entire surface of a concrete slab, all points must fall within an envelope 3/4 in. (19 mm) above or below the theoretical elevation plane. Random traffic floor finish tolerances may be specified either by the traditional 10 ft (3 m) straightedge method, shown in Fig. 1-1(b), or by the F-number system. For a complete discussion of the F-number system refer to ACI 302.1R-89, Guide for Concrete Floor and Slab Construction, and ACI Compilation No. 9, Concrete Floor Flatness and Levelness. If the 10 ft (3 m) straightedge method is used, there are three floor classifications: conventional, moderately flat, and flat. In order for a surface to meet the requirements of one of these three classifications, a minimum of 0.01 times the area of the floor measured in ft2 (0.1 times the area in m2) must be taken. Ninety percent of the samples must be within the first column shown in Fig. 1-1(b), and 100 percent of the samples must fall within the second column in Fig. 1-1(b). The orientation of the straightedge must be parallel, perpendicular, or at a 45 degree angle to the longest construction joint bounding the test surface. ACI 117, Specifications for Tolerances for Concrete Construction and Materials and Commentary, details the other requirements for taking the samples. The F-number system, diagrammed in Fig. 1-1(c), is a statistical method used to measure and specify both the local flatness of a floor within adjacent 12 in. (300 mm) intervals (the FF number) and the local levelness of a floor (the FL number) over a 10 ft (3.05 m) distance. The higher the FF or FL number, the flatter or more level the floor. To determine if a floor falls within the tolerances of a particular FF and FL, number measurements must be taken according to the procedure set forth in ASTM E1155-87. In most cases, a sophisticated instrument must be used that can take the measurements and perform the calculations necessary for determining the F numbers. Although there is no direct correlation, an FF50 roughly corresponds to a 1/8 in. (3.2 mm) gap under a 10 ft (3.05 m) straightedge. An FF25 roughly corresponds to a 1/4 in. (6 mm) gap under a 10 ft (3.05 m) straightedge.
Concrete Details 3 specified elevation +3/4" (19) -3/4" (19) (a) level alignment 10' (3 m) 10' (3 m) straightedge set anywhere on the floor (b) 10-ft straightedge method 10' (3 m) z q 12" (305) (c) F-number system 12" (305) conventional: moderately flat: flat: 1/2" (13) 3/8" (10) 1/4" (6) 3/4" (19) 5/8" (16) 3/8" (10) floor surface classification 90% compliance 100% compliance maximum gap Figure 1-1 Concrete slabs-on-grade tolerances 03 05 03 For slabs-on-grade the F-number system works well. However, to determine the F numbers, measurements must be taken within 72 hours of floor installation and, for suspended slabs, before shoring and forms are removed. Therefore, for suspended slabs, the specified levelness of a floor may be compromised when the floor deflects when the shoring is removed and loads are applied. ACI 117 gives requirements for five classes of floors that can be specified: conventional, moderately flat, flat, very flat, and superflat. In order to meet the requirements for whatever class of floor is specified, the procedures of ASTM E1155 must be followed and the test results must meet certain overall flatness (SOFF) values and specified overall levelness (SOFL) values. In addition, minimum local values for flatness and levelness must also be achieved. These are 3/5 of the SOFF and SOFL values. For example, a “conventional” floor must have an SOFF of
4 Architect’s Handbook of Construction Detailing 20 and an SOFL of 15, while a superflat floor must have an SOFF of 60 and an SOFL of 40. Refer to ACI 117 for detailed requirements. 1-2 CAST-IN-PLACE CONCRETE SECTIONAL TOLERANCES Description Figure 1-2 shows dimensional tolerances for cast-in-place concrete elements. It includes elevation tolerances as well as cross-sectional tolerances for elements such as columns, beams, walls, and slabs. ±3/4" (19) before removal of shoring ±1/2" (13) ±3/4" (19) ±1/2" (13) ±1/2" (13) ±3/4" (19) total S.O.G. see Fig. 1-1 not to scale +2" -1/2" (+51, -13) offset: class A: +1/8" (3.2) class B: +1/4" (6) class C: +1/2" (13) class D: +1" (25) +1", -1/2" (+25, -13) floor finishes, see Fig. 1-1 formed slabs: ±3/4" (19) up to 12" (305): over 12" (305) to 3' (0.90 m): over 3' (0.90 m): +3/8"-1/4" (+10, -6) +1/2", -3/8" (+13, -10) +1", -3/4" (+25, -19) ±0.3% thickness: -1/4" (6) Figure 1-2 Cast-in-place concrete sectional tolerances 03 05 04
Concrete Details 5 Limitations of Use The tolerances shown in this drawing should be used with judgment as a range of acceptability and an estimate of likely variation from true measurements, not as a basis for rejection of work. Floor tolerance measurements must be made within 72 hours after the concrete is finished and before the shoring is removed. For additional tolerances, refer to ACI 117. If smaller tolerances are required, they should be clearly indicated in the contract documents and discussed with the contractor prior to construction. Detailing Considerations In some cases tolerances may accumulate, resulting in a wider variation from true measurement than that due to individual tolerances alone. In general, higher accuracy requires a higher construction cost. A floor poured over metal decking will generally deflect significantly. If deflection must be limited, extra support or more rigid decking may be needed. Coordination Required If other materials are being used with or attached to the concrete, the expected tolerances of the other materials must be known so that allowance can be made for both. Benchmarks and control points should be agreed on by the contractor and architect prior to construction and should be maintained throughout construction. Refer to Sections 1-11 and 1-13 for tolerances of precast concrete. Allowable Tolerances The various sectional tolerances are shown diagrammatically in Fig. 1-2. The level alignment tolerance of ±1/2 in. (13 mm) for lintels, sills, and parapets also applies to horizontal grooves and other lines exposed to view. Offsets listed as Class A, B, C, and D are for adjacent pieces of formwork facing material. Note that the level alignment of the top surface of formed slabs and other formed surfaces is measured before the removal of shoring. There is no requirement for slabs on structural steel or precast concrete. The tolerance for the top of a wall is ±3/4 in. (19). For slabs-on-grade, the tolerance is −3/8 in. (−10 mm) for the average of all samples and −3/4 in. (−19 mm) for an individual sample. The minimum number of samples that must be taken is one per 10,000 ft2 (929 m2). 1-3 CAST-IN-PLACE CONCRETE PLAN TOLERANCES Description Figure 1-3 complements Fig. 1-2 and illustrates allowable variations from lateral dimensions for various concrete elements such as columns, piers, walls, and openings. The tolerances
6 Architect’s Handbook of Construction Detailing not to scale ±1/2" (13) ±1/2" (13) ±1/2" (13) +1", -1/2" (+25, -13) floor opening cross-sectional dimensions: up to 12" (305): over 12" (305) to 3' (914): over 3' (914": +3/8"-1/4" (+10, -6) +1/2", -3/8" (+13, -10) +1", -3/4" (+25, -19) offset: class A: +1/8" (3.2) class B: +1/4" (6) class C: +1/2" (13) class D: +1" (25) +1", -1/2" (+25, -13) ±1" (25) ±1" (25) ±1/2" (13) openings 12" (305) or smaller sawcuts, joints, and weakened plane embedments ±3/4" (19) ±1" (25) Figure 1-3 Cast-in-place concrete plan tolerances 03 05 05 shown in Fig. 1-3 are based on recommendations of the ACI. In some cases, the tolerances may conflict with individual ACI documents. In these cases, the tolerances required should be specified in the contract documents. Limitations of Use The tolerances shown in Fig. 1-3 should be used with judgment as a range of acceptability and an estimate of likely variation from true measurements, not as a basis for rejection of work.
Concrete Details 7 If smaller tolerances are required, they should be clearly indicated in the contract documents and discussed with the contractor prior to construction. For additional tolerances, refer to ACI 117. Detailing Considerations In some cases tolerances may accumulate, resulting in a wider variation from true measurement than that due to individual tolerances alone. Generally speaking, higher accuracy requires a higher construction cost. Details should provide sufficient clearance for the tolerances shown as well as for attached materials. Coordination Required If other materials are being used with or attached to the concrete construction, the expected tolerances of the other materials must be known so that allowance can be made for both. Benchmarks and control points should be agreed on by the contractor and architect prior to construction and should be maintained throughout construction. Refer to Sections 1-11 and 1-13 for tolerances of precast concrete. 1-4 WATERSTOPS Description A waterstop is a premolded sealant used across concrete joints to stop the passage of water under hydrostatic pressure. There are dozens of different styles and sizes of waterstops made from several types of materials to suit particular situations. Waterstops are made for two basic types of joints: working and nonworking. Working joints are those where significant movement is expected; nonworking joints are those where little or no movement is expected. Figure 1-4 shows two typical types of joints. A centerbulb waterstop is shown in the working joint in Fig. 1-4(a), which allows movement both parallel and perpendicular to the plane of the concrete. For a nonworking joint, as shown in Fig. 1-4(b), a dumbbell or flat, serrated waterstop can be used. The dumbbell shape shown here holds the waterstop in place and provides a longer path for water to travel across the joint, improving its watertightness. If a great deal of movement is expected, a U-shaped, tear-web center section can be selected, as shown in Fig. 1-4(c) Limitations of Use The details included here show only two of the many styles of waterstops available for various applications. Refer to manufacturers’ literature for specific recommendations on material and configuration of a waterstop. Detailing Considerations Most waterstops are either 6 in. (152 mm) or 9 in. (229 mm) wide; some are available up to 12 in. (305 mm).
8 Architect’s Handbook of Construction Detailing (c) tear web waterstop (a) working joint (b) nonworking joint 07 92 13 07 91 23 03 15 13 03 15 13 not less than twice the diameter of the largest aggregate reinforcing reinforcing Figure 1-4 Waterstops 03 15 13 Select the type and shape of waterstop based on the requirements of the joint, either working or nonworking. Likely Failure Points Splitting of the joint due to the use of an incorrect type of waterstop for the movement expected Leaking due to honeycombing near the seal caused by displacement of the waterstop during placing and consolidation of the concrete Leaking caused by incomplete or improper splicing Leaking caused by contamination of the waterstop by form coatings Materials 03 15 13 WATERSTOP Waterstops for general construction are typically made from polyvinyl chloride (PVC), styrene butadiene rubber (SBR), and neoprene. Other materials are available, including metal, which are resistant to certain types of chemicals or which are more appropriate for special uses.
Concrete Details 9 PVC can be easily spliced, while other materials require the use of preformed fittings for angles or the use of skilled workers to make the correct fittings and splices. The width of the waterstop should not be greater than the thickness of the wall. 07 91 23 BACKER ROD Closed cell polyethylene foam, with the diameter at least 25 percent greater than the joint width. 07 92 13 SEALANT Materials Polysulfide, polyurethane, or silicone, ASTM C920, are the most common types used. Sealant may either be Type S or M (one part or multicomponent), Grade P or NS (pourable or nonsag), and Class 25. Sealant must be compatible with the type of joint filler used. Execution Sealant depth equal to the width of the joint up to 1/2 in. (13 mm), with a minimum depth of 1/4 in. (6 mm). Sealant depth 1/2 in. (13 mm) for joint widths from 1/2 in. to 1 in. (13 mm to 25 mm). For sealants with a ±25 percent movement capability, the joint width should be four times the expected movement of the joint. Sealant should not bond to the joint filler. 1-5 SLAB-ON-GRADE CONTROL JOINT Description Figure 1-5 shows one of the three types of joints used in concrete slabs-on-grade. Control joints, also called contraction joints, are used to induce cracking in preselected locations when the slab shortens due to drying, shrinking, and temperature changes. For lightly loaded slabs, a minimum thickness of 4 in. (102 mm) is required. For most light industrial and commercial work, slab thicknesses of 5 in. or 6 in. (127 mm or 152 mm) are recommended, depending on the loading conditions. Industrial floors may require even thicker slabs. Limitations of Use The detail shown is for lightly loaded and moderately loaded interior and exterior slabs. Heavy-duty industrial floors, street pavements, and other heavily loaded slabs require special considerations for reinforcement, design thickness, and joint construction. Verify the size and spacing of rebars, if required, with a structural engineer. Detailing Considerations Control joints may be formed by sawcutting shortly after the slab hardens (as shown in Fig. 1-5), by hand tooling, or by using preformed plastic or metal strips pressed into the fresh concrete.
10 Architect’s Handbook of Construction Detailing 1/4 T 1" (25) Min. T 07 92 13 03 22 00 07 26 16 If joint is hand-tooled use 1/8" maximum radius for floors and 1/2" maximum radius for sidewalks and drives Sand, gravel or compacted earth Figure 1-5 Slab-on-grade control joint 03 30 07 For interior slabs, control joints should be placed 15 ft to 20 ft (4.6 m to 6.1 m) apart in both directions. Slab sections formed with control joints should be square or nearly square. For sidewalks or driveways control joints should be spaced at intervals approximately equal to the width of the slab, but walks or drives wider than about 12 ft (3.6 m) should have an intermediate control joint in the center. If control joints will be visible in the completed construction, their location should be planned to coincide with lines of other building elements, such as column centerlines and other joints. Isolation and construction joints can also serve as control joints. Vapor barriers should be used under slabs to prevent moisture migration into the slab, to prevent shrinkage cracks, and to provide a barrier to radon penetration. However, in order to prevent plastic and drying shrinkage caused by differential water loss between the top and bottom of the slab, the slab must be properly cured following ACI recommendations. Seal control joints to prevent spalling of the concrete. Coordination Required Select a vapor barrier and granular fill under the slab to satisfy the requirements of the project. In most cases, a gravel subbase should be placed under the slab to provide drainage. Reinforcing and concrete strength should be selected based on service requirements of the slab. The subgrade should be compacted to 95 percent of standard Proctor density prior to placing the subbase. Likely Failure Points Cracking of the slab in undesirable locations if control joints are placed farther apart than 20 ft (6.1 m) or if sections of the slab are elongated (length-to-width ratio greater than 1.5) or are L-shaped
Concrete Details 11 Cracking of the slab if control joint grooves are not deep enough Random cracking before sawing of control joints usually means that the sawing was delayed too long Materials 03 22 00 WELDED WIRE REINFORCEMENT 6 × 6 ––W1.4 × 1.4 (152 × 152 –MW9 × MW9), minimum or as required by the structural requirements of the job. Place welded wire reinforcement in the top one-third of the slab. If fabric is carried through control joints, cut every other wire to ensure that the cracking will occur at the joint. Reinforcement is often not used where frequent control joints are used. Welded wire reinforcement should extend to about 2 in. (51 mm) from the edge of the slab but no more than 6 in. (152 mm) from the edges. 07 26 16 VAPOR BARRIER 6 mil (0.15 mm) polyethylene. Permeance of less than 0.3 perm (17 ng/s • m2 • Pa) determined in accordance with ASTM E96. Barrier should not be punctured during construction activities. Edges should be lapped a minimum of 6 in. (152 mm) and taped and should be carefully fitted around openings. 07 92 13 SEALANT Materials Polysulfide, polyurethane, or silicone, ASTM C920, are the most common types used. Sealant may be either Type S or M (one part or multicomponent), Grade P or NS (pourable or nonsag), and Class 25. Sealant must be compatible with the type of joint filler used. Use epoxy resin when support is needed for small, hard-wheeled traffic. Execution Sealant depth equal to the width of the joint up to 1/2 in. (13 mm), with a minimum depth of 1/4 in. (6 mm). Sealant depth 1/2 in. (13 mm) for joint widths from 1/2 in. to 1 in. (13 mm to 25 mm). For sealants with a ±25 percent movement capability, the joint width should be four times the expected movement of the joint. Sealant should not bond to the joint filler. Thoroughly clean the joint of dirt and debris prior to application of the sealant.
12 Architect’s Handbook of Construction Detailing (a) joint design (b) isolation joint at column 1/2" (13) min. 07 92 13 03 22 00 07 91 23 03 15 11 adjacent slab, column, wall, pilaster, or other fixed element granular fill, sand, or other base as required by the project column isolation joint concrete filled around column after floor is poured Figure 1-6 Slab-on-grade isolation joint 03 30 08 1-6 SLAB-ON-GRADE ISOLATION JOINT Description Figure 1-6(a) shows one of the three types of joints used in concrete slabs-on-grade. Isolation joints, also called expansion joints, are used to structurally separate the slab from other building elements to accommodate differential movement. They are usually located at footings, columns, walls, machinery bases, and other points of restraint such as pipes, stairways, and similar fixed structural elements. Figure 1-6(b) shows the general configuration when an isolation joint is located at a column. For lightly loaded slabs, a minimum thickness of 4 in. (102 mm) is required. For most commercial work, slab thicknesses of 5 in. (127 mm) or 6 in. (152 mm) are recommended, depending on the loading conditions. Industrial floors may require even thicker slabs. Limitations of Use The detail shown here is for lightly loaded and moderately loaded interior and exterior slabs. Heavy-duty industrial floors, street pavements, and other heavily loaded slabs require special considerations for reinforcement, design thickness, and joint construction. If required, verify the size and spacing of rebars with a structural engineer.
Concrete Details 13 Detailing Considerations Isolation joint fillers must extend the full thickness of the joint. The width of isolation joints should be sized to accommodate the expected movement of the slab, allowing for about a 50 percent maximum compression of the joint. In most cases, a 1/2 in. (13 mm) joint is adequate, but wider joints may be needed for large slabs or extreme conditions. In certain noncritical locations such as garage floors, protected exterior slab/foundation intersections, and similar conditions, the sealant and backer rod may be omitted, with the joint filler placed flush with the top of the slab. Vapor barriers should be used under slabs to prevent moisture migration into the slab, to prevent shrinkage cracks, and to provide a barrier to radon penetration. However, in order to prevent plastic and drying shrinkage caused by differential water loss between the top and bottom of the slab, the slab must be properly cured following ACI recommendations. A bond breaker should be used with isolation joints if the joint filler does not serve this purpose. Coordination Required Select a vapor barrier and granular fill under the slab to satisfy the requirements of the project. In most cases, a gravel subbase should be placed under the slab to provide drainage. Reinforcing and concrete strength should be selected based on service requirements of the slab. The subgrade should be compacted to 95 percent of standard Proctor density prior to placing the subbase. Likely Failure Points Cracking of the slab near walls or columns if proper isolation joints are not formed Cracking near the isolation joint if the joint filler is displaced during construction Slab settlement if the ground under the slab is not compacted to the proper density Materials 03 22 00 WELDED WIRE REINFORCEMENT 6 × 6—W1.4 × 1.4 (152 × 152 –MW9 × MW9), minimum or as required by the structural requirements of the job. Place welded wire reinforcement in the top one-third of the slab. Reinforcement is often not used where frequent control joints are used. Welded wire reinforcement should extend to about 2 in. (51 mm) from the edge of the slab but no more than 6 in. (152 mm) from the edges. 03 15 11 EXPANSION JOINT FILLER Compressible joint fillers may be bituminous-impregnated fiberboard or glass fiber or one of several other types of joint fillers. In some situations, the joint filler may be used alone without a sealant.
14 Architect’s Handbook of Construction Detailing 07 91 23 BACKER ROD Closed cell polyethylene foam, with the diameter at least 25 percent greater than the joint width. 07 92 13 SEALANT Materials Polysulfide, polyurethane, or silicone, ASTM C920, are the most common types used. Sealant may be either Type S or M (one part or multicomponent), Grade P or NS (pourable or nonsag), and Class 25. Sealant must be compatible with the type of joint filler used. Execution Sealant depth equal to the width of the joint up to 1/2 in. (13 mm), with a minimum depth of 1/4 in. (6 mm). Sealant depth 1/2 in. (13 mm) for joint widths from 1/2 in. to 1 in. (13 mm to 25 mm). For sealants with a ±25 percent movement capability, the joint width should be four times the expected movement of the joint. Sealant should not bond to the joint filler. Thoroughly clean the joint of dirt and debris prior to application of sealant. 1-7 SLAB-ON-GRADE CONSTRUCTION JOINT Description Figure 1-7 shows two variations of a construction joint. Construction joints provide stopping points for construction activities. A construction joint may also serve as a control or isolation joint. Construction joints can be formed with separate wood strips placed on the form after the first pour to form the keyway or prefabricated forms made specifically for this purpose may be used. For lightly loaded slabs, a minimum thickness of 4 in. (102 mm) is required. For most commercial work, slab thicknesses of 5 in. (127 mm) or 6 in. (152 mm) are recommended, depending on the loading conditions. Limitations of Use The details shown here are for lightly loaded and moderately loaded interior and exterior slabs. Heavy-duty industrial floors, street pavements, and other heavily loaded slabs require special considerations for reinforcement, design thickness, and joint construction. Verify the size and spacing of dowels, if required, with a structural engineer. Butt-type construction joints (those without reinforcing dowels, or keyed joints) should be limited to lightly loaded slabs 4 in. (102 mm) thick. Detailing Considerations Construction joints should not be placed closer than 5 ft (1525 mm) to any other parallel joint.
Concrete Details 15 (a) construction joint with keyway (b) construction joint without keyway T T/4 Bond breaker 1:3 Slope Edge 03 21 00 03 22 00 Edge T T/2 Bond breaker Figure 1-7 Slab-on-grade construction joint 03 30 09 A bond breaker must be used with construction joints. Vapor barriers should be used under slabs to prevent moisture migration into the slab, to prevent shrinkage cracks, and to provide a barrier to radon penetration. However, in order to prevent plastic and drying shrinkage caused by differential water loss between the top and bottom of the slab, the slab must be properly cured following ACI recommendations. The top of the joint should be given a slight radius edge to avoid spalling of the concrete. Coordination Required Select a vapor barrier and granular fill under the slab to satisfy the requirements of the project. In most cases, a gravel subbase should be placed under the slab to provide drainage. Reinforcing and concrete strength should be selected based on service requirements of the slab. The subgrade should be compacted to 95 percent of standard Proctor density prior to placing the subbase. Likely Failure Points Cracking caused by misaligned dowels in construction joints Cracking due to omission of the bond breaker on the joint or one end of the dowel Slab settlement if the ground under the slab is not compacted to the proper density
16 Architect’s Handbook of Construction Detailing Materials 03 21 00 REINFORCING DOWELS Materials Use reinforcing dowels in construction joints for heavily loaded floors and where wheeled traffic is present. #6 (#1) rebar for slabs 5 in. (127 mm) to 6 in. (152 mm) deep. #8 (#25) rebar for slabs 7 in. (178 mm) to 8 in. (203 mm) deep. Minimum 16 in. (406 mm) long dowels for 5 in. (127 mm) to 6 in. (152 mm) slabs; minimum 18 in. (457 mm) dowels for 7 in. (178 mm) to 8 in. (203 mm) slabs. Execution Space 12 in. (305 mm) on center. A dowel extending into the second pour must be coated with bond breaker. Align and support dowels during pouring. 03 22 00 WELDED WIRE REINFORCEMENT 6 × 6—W1.4 × 1.4 (152 × 152 –MW9 × MW9), minimum or as required by the structural requirements of the job. Place welded wire reinforcement in the top one-third of the slab. Temperature reinforcement is often not used where frequent control joints are used. Welded wire reinforcement should extend to about 2 in. (51 mm) from the edge of the slab but no more than 6 in. (152 mm) from the edges. 1-8 CAST-IN-PLACE CONCRETE WALL WITH INSULATION Description Figure 1-8 shows two basic methods of detailing a cast-in-place wall to include insulation and interior finish. Figure 1-8(a) shows the use of stud framing to provide a space for insulation as well as the substrate for the interior finish. Figure 1-8(b) illustrates the application of rigid insulation directly to the concrete, with the finish being applied to smaller framing. As an alternative, Z-shaped furring strips can be attached to the concrete. However, furring attached directly to the concrete creates a thermal bridge and reduces the overall R-value slightly. Depending on the building use, separate framing is useful to provide space for additional insulation as well as space for electrical service and plumbing pipes. In both cases a window jamb is shown, but the door framing is similar. One of the detailing problems with cast-in-place concrete is accommodating construction tolerances, both for the opening size and for the window or door, which is usually steel or aluminum. ACI tolerances allow for an opening to be oversize by 1 in. (25 mm) or undersized by 1/2 in. (13 mm). This means that at each jamb, the edge of the concrete opening may be larger by 1/2 in. (13 mm) or smaller by 1/4 in. (6 mm). Tolerances for steel door frames at each jamb are 1/16 in. (1.6 mm) larger or 3/64 in. (1.2 mm) smaller than their listed dimension. To allow for tolerances and a workable sealant joint, the design dimension of the concrete
Concrete Details 17 07 92 13 07 92 13 (a) stud framing with batt insulation (b) direct application of insulation concrete opening 1" (25) larger than window or door dimension concrete reinforcing as required 07 91 23 07 91 23 07 21 16 07 26 13 min. 1" (25) air space 07 21 16 if required 07 21 13 07 26 13 wallboard trim and sealant gypsum wallboard blocking as required wallboard trim and sealant Figure 1-8 Cast-in-place concrete wall with insulation 03 30 53 opening shown in Fig. 1-8(a) should be 1 in. (25 mm) wider than the width of the door or window frame (1/2 in. [13 mm] at each jamb). This allows the concrete to be undersized and the frame to be oversized while still allowing sufficient space for sealant. Figure 1-8(b) illustrates the use of a notch in the concrete to account for construction tolerance issues. In this case, variations in opening size or frame size can be accommodated with blocking in the notch and covered with interior finish or trim. Although notching the concrete increases the formwork costs slightly, it accommodates tolerances and maintains a uniform joint width for sealant. Limitations of Use These details do not include requirements for the concrete wall. Refer to Section 1-9 and ACI requirements for formwork, concrete composition, and reinforcement.
18 Architect’s Handbook of Construction Detailing Detailing Considerations Maintain an air space of at least 1 in. (25 mm) between the inside face of the concrete and the batt insulation to minimize thermal bridging through the studs and avoid possible wetting of the insulation from any moisture that might penetrate the concrete wall. If joints in the concrete are well sealed, the concrete will act as an air barrier. Joints between the roof and floor structure should be well sealed to maintain the continuity of the air barrier. Refer to Section 5-5 for more information on air barriers. Verify the need for a vapor retarder and its location. Place it as shown on the warm side of the insulation in a cool or cold climate. Refer to Section 5-5 for more information on vapor retarders. Window sills should be detailed with flashing (including end dams) to drain any moisture to the outside. Maximum furring or stud spacing is 24 in. (610 mm) on center. Precast concrete insulated panels can also be used in lieu of cast concrete. This construction eliminates thermal bridging and provides an extra layer of insulation. Foam insulation must be covered with a code-approved thermal barrier. This is a minimum 1/2 in. (13 mm) layer of gypsum wallboard. Refer to Section 1-9 for information on architectural concrete. Likely Failure Points Degradation of foam plastic insulation if a compatible adhesive is not used Degradation of batt insulation if subjected to moisture Air leakage due to an inadequate seal between concrete and framing Moisture penetration due to lack of an adequate seal between vapor retarder and framing Materials 07 21 16 BATT INSULATION Fiberglass, ASTM C665, Type I or Type II (unfaced or faced). Mineral fiber, ASTM C553. Apply in the thicknesses required for thermal resistance. 07 21 13 BOARD INSULATION Materials Polyisocyanurate foam board, ASTM C591. Extruded polystyrene, ASTM C578. Apply in the thicknesses required for thermal resistance. Verify compatibility with the adhesive used. Execution If mastic is applied, use a full adhesive bed or grid of adhesive. Insulation may be installed with metal or plastic stick clips placed in a grid pattern. Follow manufacturers’ recommendations for spacing. Metal clips provide a minor thermal bridge.
Concrete Details 19 07 26 13 VAPOR RETARDER 4 mil (0.1 mm) polyethylene film, 0.08 maximum perm rating. 07 92 13 ELASTOMERIC JOINT SEALANT Materials Solvent-based acrylic, ASTM C834. Acrylic latex may also be used. One-part polyurethane, ASTM C920, Type S, Grade NS, Class 25 or 50, as required. One-part silicone, ASTM C920, Type S, Grade NS, Class 25 or 50, as required. Execution Sealant depth equal to the width of the joint up to 1/2 in. (13 mm), with a minimum depth of 1/4 in. (6 mm). See Section 5-38 for methods of sizing joints. 07 91 23 BACKER ROD Closed cell foam, ASTM D1056, Type 2. 25 percent to 33 percent larger than joint width. 1-9 ARCHITECTURAL CONCRETE Description Architectural concrete is exposed concrete that is intended to act as a finished surface either on the interior or exterior of a structure. Special attention is required in detailing and specifying architectural concrete to ensure that the final appearance has minimal color and texture variation and minimal surface defects when viewed from a distance of 20 ft (6.1 m). Although there are many considerations in achieving a quality architectural concrete surface, including concrete mix, curing, and finishing procedures, Fig. 1-9 illustrates some of the primary considerations for detailing openings, joints, formwork, and reinforcement placement. Limitations of Use Refer to ACI 303R for additional recommendations concerning concrete mix, requirements for forms, curing, and methods of treating and finishing the concrete surface. Detailing Considerations Best results are obtained when large areas of concrete are constructed with textured forms or have textured finishes. Joint layout should be designed to divide large concrete surfaces into manageable sections for construction. Horizontal control joints may be needed at the top and bottom of openings in walls.
20 Architect’s Handbook of Construction Detailing interior finish not shown for clarity 03 11 16 03 11 00 03 21 00 forms 3/4" (19) clear minimum #11 (#36) bars and smaller 2" drip 15o min. Figure 1-9 Architectural concrete 03 33 00 Common vertical cracking in walls can be concealed with vertical rustication joints at the midspan of bays unless other vertical joints are provided. In long walls, vertical cracking can be controlled by providing construction joints not more than 20 ft (6.1 m) on center or by placing deep, narrow rustication strips on both sides of the wall to induce cracking. The depth of this type of joint should be 1.5 times the maximum aggregate size. Sills and similar horizontal surfaces should be sloped to encourage washing of airborne dirt from the concrete by rainwater. Smooth surfaces should have a minimum slope of 1:12, while extremely textured surfaces may have a slope of up to 1:1. Parapets should slope away from the face of the concrete.
Concrete Details 21 Recommended joint depths are 3/4 in. (19 mm) for small rustication or pattern grooves and 11/2 in. (38 mm) for control joints and panel divisions. Generally, avoid right and acute angle corners because of the difficulty of form removal without potential damage during construction. Use chamfer strips on right angle corners. Wood chamfer strips should have a minimum face width of 1 in. (25 mm) and be spliced only at concrete joints. Drips should be cast into all horizontal offsets and placed as near to the exterior surface as possible but not closer than 11/2 in. (38 mm). Refer to Section 1-8 for information on insulation and interior finish details. Coordination Required Joint locations must also meet the structural requirements of the wall. Regions of flexural tension in beams and other elements should be identified with the help of the structural engineer so that the depths of rustication strips can be kept to a minimum. The increased concrete cover over reinforcing due to the strips can cause any cracks that occur to be wider than they normally would be with less concrete cover. Likely Failure Points Defects on the surface caused by leakage from form joints Form joints must be made grout-tight. This can be done by using low-slump concrete, using various types of liners, using pressure-sensitive rubber gaskets, or caulking and using a lumber batten backing. Materials 03 21 00 REINFORCING STEEL The clear distance between forms and reinforcing bars should be 2 in. (51 mm), 1.25 times the bar size, or 1.5 times the maximum aggregate size, whichever is largest. This is done to minimize the chance of rust stains and to facilitate the placement of the concrete. If part of the concrete will be removed after removal of forms, additional coverage should be provided. The clear distance between bars should be 2 in. (51 mm), 1.25 times the bar diameter, or 1.75 times the maximum aggregate size, whichever is largest. Horizontal reinforcing in walls should be 1.5 times the ACI 318 minimum to minimize the width of cracks. Horizontal reinforcing crossing construction joints or control joints formed by deep rustication strips should not exceed one-half of the horizontal reinforcement elsewhere in the wall. Tie wire, chairs, spacers, and bolsters should be stainless steel. 03 11 16 RUSTICATION STRIP Wooden strips used for rustication joints should have a width at least equal to their depth. Metal strips should have a minimum width of 3/4 in. (38 mm).
22 Architect’s Handbook of Construction Detailing Strips used to form joints should be angled at least 15 degrees to allow for removal. End joints of insert strips should be mitered and tightly fitted. 03 11 00 FORM TIE Various types of form ties can be selected, depending on the appearance desired. Cones are available that will form a hole up to 2 in. (51 mm) deep and about 1 in. (25 mm) in diameter. Cones from he-bolt form ties leave a hole 1 in. to 2 in. (25 mm to 51 mm) in diameter. Cones from she-bolt form ties leave a hole 3/4 in. to 11/2 in. (19 mm to 38 mm) in diameter, depending on the strength category of the tie. Snap ties will result in holes about 1/4 in. (6 mm) in diameter and about 1 in. (25 mm) deep but leave a rough appearance and are usually not used for architectural concrete. Tie holes may be patched or left as cast for architectural effect. 1-10 PRECAST CONCRETE SPANDREL WITH INSULATION Description Figure 1-10 illustrates a common method of detailing a precast concrete panel on a cast-inplace concrete structural frame. Details for precast panels on a steel frame are similar. While this detail indicates panel attachment to concrete structural columns at either end of the panel, panels may also be attached at the floor line, as shown in Figs. 1-19 and 1-20. For a full discussion of precast concrete design, refer to Architectural Precast Concrete, published by the Precast/Prestressed Concrete Institute. Limitations of Use This detail shows a cladding panel not intended to support any additional gravity loads other than its own weight, wind, seismic forces, and the load of the window system. This detail illustrates the use of an open precast frame for the window unit. That is, the four sides of the window opening are separate precast units. Closed window openings are entirely contained in one panel and are generally more economical than open designs. Because there are many possible variations in panel configuration and attachment methods, this detail shows only one possible method of detailing. Specific project details must be based on the structural requirements of the building, climate, types of windows used, interior finish requirement, exterior panel appearance, and the preferred methods of casting by the local precaster. Detailing Considerations Locate the window frame a minimum of 2 in. (51 mm) from the face of the precast panel to avoid water dripping from the panel across the window. Precast panel connections should provide for adjustability in three dimensions. Panel connections should allow for a concrete beam and slab tolerance of ±3/4 in. (38 mm), a horizontal location of beam edge tolerance of ±1 in. (25 mm), and a precast panel tolerance of +1/4 in. (6 mm).
Concrete Details 23 reinforcing not shown for clarity ±1/4" (6) opening height tolerance between panels precast precast panel attached at columns; verify details with structural engineer and precast supplier precast tieback connection as required additional batt insulation if required 1-1/2" (38) min. clearance; 2" (51) preferred slope 2% min. window assembly with weeps aluminum sill trim gypsum wallboard on metal studs 07 21 16 07 21 29 07 26 13 07 92 13 & 07 91 23 fire safing insulation and smoke seal as required shim and attach window assembly to precast as recommended by precast supplier ceiling wallboard trim and sealant if required drip 1-1/2" (38) minimum window assembly with slip joint 2" (51) min. seal shim space with vapor retarder tape if required Figure 1-10 Precast concrete spandrel with insulation 03 40 01 If a rough texture is specified for the precast panel, specify the extent of the texturing to provide for a smooth surface where window framing and sealant are installed. Hold the concrete texturing at least 1/2 in. (13 mm) from the interface of the precast and the window frame. Provide flashing with end dams under the window sill if required.
24 Architect’s Handbook of Construction Detailing Verify the need for a vapor retarder based on climate and building use. If spray polyurethane foam is used, a thermal barrier may be required by the local building code. A 1/2 in. (13 mm) layer of gypsum wallboard is usually sufficient for this purpose. Coordination Required Develop panel sizes and connection methods with the structural engineer to minimize deflection and movement of each panel and to avoid conflicts between connections and interior finish requirements. Coordinate with the precast supplier to determine the most economical configuration for panels, proper draft for casting (see Section 1-15), attachment methods, erection sequencing, and other aspects of panel manufacturing. Consider window washing methods when recessing windows deeply into precast units. Use stainless steel, galvanized steel, or plastic for trim, inserts, flashing, and other items incorporated into the precast. Other materials require separation with dielectric materials. Materials 07 21 16 BATT INSULATION Fiberglass, ASTM C665, Type I or Type II (unfaced or faced). Mineral fiber, ASTM C553. Apply in thicknesses as required for thermal resistance. 07 21 20 SPRAYED INSULATION Closed cell polyurethane foam, ASTM C1029. Open cell Icynene foam. 07 26 13 VAPOR RETARDER ASTM C1136. 4 mil (0.1 mm) polyethylene film, 0.08 (4.6 ng/s • m2 • Pa) maximum perm rating. 07 91 23 BACKER ROD Closed cell foam, ASTM D1056, Type 2. 25 percent to 33 percent larger than joint width. 07 92 13 SEALANT Materials Solvent-based acrylic, ASTM C834. Acrylic latex may also be used. One-part polyurethane, ASTM C920, Type S, Grade NS, Class 25 or 50, as required. One-part silicone, ASTM C920, Type S, Grade NS, Class 25 or 50, as required.
Concrete Details 25 Execution Sealant depth equal to the width of the joint up to 1/2 in. (13 mm), with a minimum depth of 1/4 in. (6 mm). See Section 5-38 for methods of sizing joints. 1-11 PRECAST CONCRETE BEAM AND DOUBLE TEE TOLERANCES Description Figure 1-11 gives some of the primary size tolerances of two types of precast concrete structural elements. As with cast-in-place concrete, knowing these tolerances is important for developing connection details between structural components and for detailing other building materials that may use the concrete structure as a substrate. During construction, one surface is usually designated as the primary control surface, the location of which is controlled during erection. Limitations of Use These guidelines are generally considered standard in the industry. If closer tolerances are required, they should be clearly indicated on the drawings and specifications. These tolerances are for components whose appearance is not critical. See Section 1-13 for architectural precast tolerances. Detailing Considerations In general, fabrication and erection costs are proportional to the level of tolerance required. Tolerances higher than industry standard should not be specified unless they are absolutely necessary. Tolerances may be cumulative between two elements or between a structural element and another building component that has its own tolerance. Erection tolerance from the theoretical building grid is ±1/2 in. (13 mm). Horizontal alignment tolerance for beams is ±1/4 in. (6 mm) for architectural edges where appearance is important and ±1/2 in. (13 mm) for visually noncritical edges. Horizontal end alignment tolerance for double tees is ±1 in. (25 mm). The erection tolerances of the primary control surface are not additive to the product tolerances shown in Fig. 1-11. See Section 1-23 for more information on precast erection tolerances. Coordination Required Required tolerances for each project should be included in the specifications so that there is no misunderstanding. Reference should be made to industry standard publications, such as ACI 117, or specific tolerances should be itemized, especially if they deviate from normal trade practices.
26 Architect’s Handbook of Construction Detailing variation from specified camber: ±1/8" per 10', 3/4" max. (±3 mm per 3 m, ±19 max.) length of element ±3/4" (19) ±1/4" (6) ±1/4" (6) stem width ±1/4" (6) ±1/4" (6) tendons: individual ±1/4" (6) bundled ±1/2" (13) ±1" (25) ±1/4" (6) sleeves ±1" (25) embedment sweep: up to 40' (12 m): 40' to 60' (12 m to 18 m): over 60' (18 m): ±1/4" (6) ±1/2" (13) ±5/8" (16) +1/4", -1/8" (+6, -3) ±1/4" (6) ±1" (25) ±1" (25) ±1/4" (6) ±1/2" (13) plates ±1/4" (6) ±1" (25) flange squareness: ±1/8" per 12" width, ±1/2" max. (±3 mm per 300 mm width, ±13 mm max.) sweep: up to 40' (12 m): 40' to 60' (12 m to 18 m): over 60' (over 18 m): ±1/4" (6) ±3/8" (10) ±1/2" (13) (a) precast concrete beam (b) precast concrete double tee Figure 1-11 Precast beam and double tee tolerances 04 41 00
Concrete Details 27 1-12 AUTOCLAVED AERATED CONCRETE PANELS Description Autoclaved aerated concrete (AAC) is a concrete-like material made with portland cement, lime, water, silica sand or recycled fly ash, and an expanding agent, such as aluminum powder. When combined and poured into molds, the aluminum reacts with the lime and cement to form microscopic hydrogen bubbles, expanding the mixture by about five times its original volume. Once the mixture has partially hardened, it is cut to size and steam-cured in a pressurized autoclave. ACC is typically formed into blocks or panels for use as exterior walls, floors, and roofs and interior partitions. Blocks are typically 8 in. by 8 in. by 24 in. (200 mm by 200 mm by 600 mm), and panels are available in thicknesses from 2 in. to 15 in. (50 mm to 375 mm), 24 in. (600 mm) wide, and up to 20 ft (6000 mm) long. Bond beams and other specialized shapes are also available. The size availability of all products depends on the manufacturer. ACC is formed to varying densities, depending on the strength required. Compressive strengths of 290 psi (2.0 Mpa), 580 psi (4.0 Mpa), and 870 psi (6.0 Mpa) are available. Because of its structural qualities and limitations, ACC is typically used as a bearing material for residential or commercial low- to mid-rise buildings, but it can be used as nonstructural cladding for buildings of any height, especially when its qualities of fire resistance, light weight, thermal mass, and sound insulation are desired. Figure 1-12 shows one possible use of an ACC panel product in a load-bearing application. ACC provides many advantages as a building material. It is structurally sound, lightweight (about 20 to 50 lbm/ft3 or 400 to 800 kg/m3), easily cut in the field, fire resistant, dimensionally stable, functions as a thermal mass, and is thermally and acoustically insulating. In addition, it has many sustainable benefits. ACC is made of plentiful raw materials, and some products use recycled fly ash instead of sand. The product does not produce indoor air quality problems, nor are pollutants produced in its manufacture. ADD can be reused or ground up for use in other products at the end of a building’s life cycle. The most problematic part of manufacturing is the use of energy in the autoclaving and drying process. Panels are assembled on a thin mortar bed on the foundation with anchoring as recommended by the manufacturer. Panels used for walls can be oriented vertically or horizontally, while floor and roof panels are laid flat. Additional reinforcing bars or straps are used as required by the structural needs of the building and to anchor other building materials to the ACC. Refer to Section 2-15 for information on AAC unit masonry. Because of its closed-cell formation, ACC is lightweight and can be cut with common power or hand tools. Shapes, reveals, signage, and other effects can also be carved or routed into the material. The R-value of ACC is approximately 1.25 hr-ft2-◦F/Btu per inch (8.66 RSI/m), depending on the density, with the added benefit of having thermal mass, which can increase its effective R-value, especially in warmer climates. Because the product is uniform throughout, there is no thermal bridging due to studs or other framing. More information can be obtained from individual manufacturers and from the Autoclaved Aerated Concrete Products Association. Limitations of Use Currently, there are only a few ACC manufacturing plants in the United States, all located in Texas, Arizona, Florida, and Georgia. Although ACC is lightweight, its shipping costs may be excessive for delivery to northern locations.
28 Architect’s Handbook of Construction Detailing Figure 1-12 Autoclaved aerated concrete panels 04 22 23.1 09 24 23 03 45 00 wood, aluminum, or steel window; see Chapter 6 for window details floor finish as required waterproof membrane insulation as required, see Section 5-4 dowel into slab and foundation per structural design anchor strap or other anchoring as recommended by structural engineer and ACC manufacturer 8" (200) min. 1/8" (3) mortar bed gypsum wallboard on pressure-treated furring or on metal Z-furring; wallboard trim and sealant as required. anchor bar set in epoxy filled hole 1/8" (3) mortar bed bond beam roof panel with rebar in grout-filled key joints slope sheet metal coping fastened with clips anchor blocking to ACC parapet block suspended ceiling or gypsum wallboard on ACC roof panel sheet metal flashing or precast concrete sill Because construction with ACC is relatively new in the United States, it may be difficult to find skilled contractors and workers. Additional time may be required for the ACC to dry thoroughly to stabilize at its long-term moisture content of 4 percent to 8 percent. In some climates or where construction schedules are short, dehumidifiers may be required to hasten the drying process. Exterior finishes should be vapor permeable, and vapor barriers on the interior
Concrete Details 29 should be limited when possible. Verify specific applications and construction details with the manufacturer. Blocking applied and attached to the ACC should be pressure treated. Detailing Considerations Building with ACC is specific to each manufacturer. Consult with the manufacturer for materials recommended for mortar, grout, anchoring, miscellaneous fasteners, and other accessories. Roofs may be constructed of ACC panels, wood trusses, or other structural material as recommended by the engineer and as required by the design of the building. If ACC panels are used for a flat structural roof, use tapered insulation to provide drainage. Details of window and door openings may vary slightly, depending on the type of frame used. Wood frames should include a rough buck attached to the ACC. Aluminum frames may be attached directly. Verify suggested attachment of frames with the ACC manufacturer. Figure 1-12 shows a wood frame with a sheet metal sill and flashing on rough wood framing. A precast concrete sill may also be used; however, flashing should be installed under the concrete sill. Coordination Required Verify all structural requirements with the structural engineer and manufacturer. Exterior finish should be vapor-permeable, polymer-modified stucco. Brick and other cladding may also be used. When wall and roof panels are used together, an airtight envelope is created. If possible, the building should be allowed to dry for several months before enclosing it. Alternately, the heating, ventilating, and air-conditioning (HVAC) system can be used to dehumidify the air. Interior wall finishes for ACC panel products are commonly mineral-based plaster applied about 1/8 in. (3 mm) thick or gypsum wallboard placed on pressure-treated furring strips. Metal furring can also be used if additional space is required for insulation or electrical services. Interior wall tile can be applied using a thin-set mortar or organic adhesive over a portland cement or gypsum-based base coat applied to the ACC. As adjacent floor panels are well aligned, floor finishes such as carpet, resilient tile or sheet goods, ceramic tile, and linoleum can be placed directly over the ACC. However, in some cases, it may be necessary to apply a topping, such as gypsum, over the ACC to provide a smooth subsurface for finish materials. Materials 03 45 00 AUTOCLAVED AERATED CONCRETE PANEL ASTM C1452. Strength class ACC 2.0, ACC 4.0, or ACC 6.0 as required. Foundation attachment and reinforcing as required by the structural engineer and manufacturer.
30 Architect’s Handbook of Construction Detailing 09 24 23 STUCCO Portland cement, polymer-modified stucco. Apply according to ASTM C926 or as recommended by the ACC manufacturer. 1-13 ARCHITECTURAL PRECAST CONCRETE PANEL TOLERANCES Description Figure 1-13 shows some of the manufacturing tolerances for precast panels commonly used as exterior cladding. These tolerances are some of the most common ones with which architects ±1/4" (6) panel face alignment: ±1/4" (6) ±1/4" (6) ±1/4" (6) ±1/4" (6) ±1" (25) difference between two diagonals ±1/8" per 6' or ±1/2" total, whichever is greater (±3 per 1830 or 13) panel dimensions when exposed to view: under 10': (under 3 m): 10' to 20': (3 m to 6 m): 20' to 40': (6 m to 12 m): ea. add. 10' over 40': (ea. add. 3 m over 12 m): ±1/8" (±3) +1/8",-3/16" (+3, -5) ±1/4" (±6) ±1/16" (±1.5 per 3 m) not to scale weld plates panel thickness: +1/4", -1/8" (+6, -3) panel opening jog between exposed edges: ±1/4" (6) max. between nonexposed edges: ±1/2", (13) joint width: ±1/4" (6) flashing reglet ±1/4" (6) ±1/8" (3) ±1/2" (13) inserts warping: 1/16" per foot of distance from nearest adjacent corner (1.5 mm per 300 mm) bowing: ± max. 1" (25) panel dimn. 360 architectural features and rustications sleeve ±1/2" (13) joint taper: 1/4" (6) over 10' (3 m) length 3/8" (9) maximum Figure 1-13 Architectural precast panel tolerances 03 45 13
Concrete Details 31 are concerned. They can serve as a guideline for developing details of panel connections and for coordination of details with other materials. Manufacturing tolerances must be coordinated with erection tolerances and tolerances for other building systems. During construction, one surface is usually designated as the primary control surface, the location of which is controlled during erection. The product tolerances given in this section are not additive to the erection tolerances of the primary control surfaces. However, product tolerances are additive to secondary control surface erection tolerances. Refer to Tolerance Manual for Precast and Prestressed Concrete Construction (MNL-135), published by the Precast/Prestressed Concrete Institute, for more information. Limitations of Use These tolerances apply to architectural panels, spandrels, and column covers. These guidelines are generally considered standard in the industry. If closer tolerances are required, they should be clearly indicated on the drawings and specifications. Requirements for closer tolerances should be reviewed with the precaster to determine the cost and scheduling consequences of tighter tolerances. Detailing Considerations Sufficient clearance between precast units and the structural frame should be provided to allow for the erection of the precast without having to alter its physical dimensions or deviate from detailed structural connections. In some cases, allowable tolerances for steel or concrete framing in tall buildings may require that attachment of precast elements follow the frame up the height of the building without being in a true plane. Details should be developed so that architectural precast elements overlap cast-in-place framing. This conceals any differential tolerances in the two materials. Bowing is an overall out-of-plane condition in which the corners of the panels may be in the same plane but the portion between the corners is out of plane. Warping, on the other hand, is an out-of-plane condition in which the corners do not fall in the same plane. Both conditions can affect the alignment and appearance of panels. The difference between diagonals applies to major openings as well as to the panel itself. The likelihood of bowing or warping is decreased if the panel contains ribs or other design features that provide additional stiffness. In some instances, the higher cost of tooling required for close tolerances may be offset by the use of a highly repetitive panel product. Coordination Required Required tolerances for each project should be included in the specifications so that there is no misunderstanding. Reference should be made to industry standard publications, such as ACI 117, the AISC Code of Standard Practices, and the Tolerance Manual for Precast and Prestressed Concrete Construction or specific tolerances should be itemized, especially if they deviate from normal trade practices.
32 Architect’s Handbook of Construction Detailing 1-14 ARCHITECTURAL PRECAST PANEL SIZE AND CONFIGURATION Description Figure 1-14 illustrates some of the considerations for determining the size, general configuration, and typical detailing requirements for non-load-bearing architectural precast concrete Figure 1-14 Architectural precast panel size and configuration 03 45 14 (a) precast size and configuration considerations (b) sequential precasting T W H open shape aggregate see Table 1-1 closed shape 1st piece cast face down with rebar extended 2nd piece cast face down while first piece is temporarily supported cold joint